Rotary piston engine

ABSTRACT

A rotary piston engine comprises a housing (1) spatially limiting a working chamber (2), an intake connection (4) for guiding gas into the working chamber (2), a pressure connection (6) for guiding the gas out of the working chamber (2), and a rotor assembly (4) having a first rotor (14) rotatably arranged in a first working sub-chamber (12) and a second rotor (21) cooperating with the first rotor (14) and rotatably arranged in a second working sub-chamber (13). The rotary piston engine also comprises a ventilation channel (8), formed in the housing (1) and connected to the working chamber (2) via a ventilation channel opening (9), for the temporally limited introducing of air into the working chamber (2), wherein the ventilation channel opening (9) is open at least in sections, in particular completely open, in a compression phase.

The present patent application claims the priority of the German patent application DE 10 2018 203 992.5, the content of which is incorporated herein by reference.

The invention relates to a rotary piston engine, in particular a claw machine, which can be operated, for example, as a compressor, a vacuum pump or a blower. The invention is further directed to a method for operation of a corresponding rotary piston engine.

Rotary piston pumps with rotary pistons which run into one another are generally known from the prior art by public prior use.

The invention is based on the problem of creating an improved rotary piston engine. In particular, it is intended to be particularly effective, in particular in relation to its intake capacity, and to be extremely long-lasting. A correspondingly improved method for operation of a rotary piston engine is also intended to be provided.

This problem is solved according to the invention by the features specified in the main claims 1 and 16. The crux lies in the fact that, in the housing, in particular precisely one ventilation channel is formed, which temporarily produces—directly or indirectly—fluid communication between the working chamber or at least one of the working sub-chambers, in particular the first working sub-chamber, and the environment. The ventilation channel opens out into the working chamber via a, in particular precisely one, ventilation channel opening, in particular on the pressure side.

In the compression phase the ventilation channel is open, so that air, in particular ambient air with ambient pressure, gets into the working chamber from outside. In the case of an at least partial opening of the ventilation channel opening, supply of air into the working chamber from outside is possible.

In particular, the ventilation channel or the ventilation channel opening is open in a suction phase or in a suction cycle, which, depending on an operating point, leads to an expansion or ventilation of the space in the housing of the rotary piston engine or of the gas located there, which space is in direct or indirect fluid communication with the ventilation channel or ventilation channel opening..

Thermal loads on parts of the rotary piston engine, such as by bearing/s and shafts, can thus be reduced effectively by the introduced air. The introduced air generally has a lower energy level. The effectiveness of the rotary piston engine is therefore particularly high. In particular, the vacuum level of the rotary piston engine remains undisturbed as a result of the temporary introduction of air into the working chamber during the compression phase. The introduced air reduces the inner compression.

When the ventilation channel opening is completely closed, supply of air into the working chamber from outside is prevented.

It is advantageous if, during operation, the first and/or second rotor sweeps past the ventilation channel opening. Preferably, the first and/or second rotor sweeps past the pressure connection opening and/or the intake connection opening.

It is advantageous if the ventilation channel is substantially circular in cross-section. The ventilation channel opening is preferably smaller, in particular substantially smaller, than the pressure connection opening and/or the intake connection opening. It preferably has a surface area of between 10 mm² and 200 mm², preferably between 20 mm² and 100 mm². The surface area of the ventilation channel opening is conveniently between 1% and 10%, preferably between 2% and 10%, preferably between 2% and 5%, of the surface area of the intake connection opening. It is advantageous if it is between 7% and 20%, preferably between 10% and 16%, of the surface area of the pressure connection opening.

The housing conveniently has a housing base part and a first and second end part connected to the housing base part. The end parts are preferably connected to the housing base part, in particular releasably, opposite one another.

The working chamber preferably has a cross-section which is formed by two intersecting circles producing an “8”.

Gas can be introduced into the working chamber or into the working sub-chambers via the intake connection. It is advantageous if the intake connection opens out into the working chamber or at least one of the working sub-chambers via at least one intake connection opening. The intake connection opening is located in an intake region of the rotary piston engine.

Gas can be discharged from the working chamber or from a working sub-chamber via the pressure connection, in particular under positive pressure or negative pressure. It is advantageous if the pressure connection is connected to the working chamber or at least one of the working sub-chambers, in particular the first working sub-chamber, via at least one pressure connection opening. The pressure connection opening is located in a pressure region of the rotary piston engine.

Each working sub-chamber is preferably outwardly spatially limited by a working-chamber wall of the housing, which runs in an arcuate manner at least in regions on the inside. The associated rotor sweeps along the working-chamber wall.

The rotors conveniently work contactlessly and are preferably embodied differently. They are matched to one another. During operation, preferably they rotate in opposite directions to one another and then conveniently mesh at least temporarily with one another. Each rotor preferably has at least two rotor blades, which are preferably like claws. Each rotor blade preferably has a claw and a claw recess. It is expedient if the first and/or second rotor, depending on the respective rotary position, at least temporarily controls or influences, in particular closes or releases, the intake connection and/or pressure connection, in particular on the end face, with its rotor blades.

Further advantageous configurations of the invention are specified in the subordinate claims.

The rotary piston engine according to subordinate claim 2 is particularly efficient. The operating pressure or the end pressure of the rotary piston engine is achieved in one stage or in one step, in particular starting from an atmospheric pressure.

The first rotor according to subordinate claim 3 is arranged or formed in such a way that it controls or influences the ventilation channel opening in its effective opening cross-section, in particular on the end face, in particular with its rotor blades. Depending on the respective rotary position of the first rotor, the ventilation channel opening is completely released, completely closed or partially releasediclosed. Conveniently, the first rotor forms a control piston.

In the common working-space phase of the rotors according to subordinate claim 4, the ventilation channel opening is completely closed, so that a supply of air from outside is avoided. In the common working-space phase, a first working sub-space spatially limited by the first rotor in the first working sub-chamber is preferably in fluid communication with a second working sub-space spatially limited by the second rotor in the second working sub-chamber. The working sub-spaces adjoin one another. They are located preferably on a common side of the rotary piston engine. It is expedient if the second rotor forms a delivery piston.

According to subordinate claim 5, in the common working-space phase the pressure connection is completely closed. This preferably takes place by way of the first rotor and the second rotor. Therefore, an extremely effective compression of the gas in the working chamber is possible. An output of the gas from the working chamber in the common working-space phase is prevented.

According to subordinate claim 6, in the common working-space phase there is a free dead space at least temporarily between the rotors. It is expedient if the dead space is located in a central region of the working chamber.

The configuration according to subordinate claim 7 allows a particularly simple and efficient achievement of the operating pressure.

The configuration according to subordinate claim 8 effectively prevents the rotor assembly from pushing the gas out via the ventilation channel.

The configuration according to subordinate claim 9 allows the gas to be pushed out of the working chamber safely via the pressure connection.

The ventilation channel opening according to subordinate claim 11 is arranged in a pressure region of the rotary piston engine. Here, there is a pressure that is altered such as increased or reduced, compared to the original, in particular atmospheric, pressure. The ventilation channel opening is thus arranged at a distance from an intake region of the rotary piston engine.

According to subordinate claim 12, the ventilation channel opening is arranged alongside, but at a distance from, the pressure connection opening of the pressure connection. In particular, the ventilation channel opening is arranged upstream of the pressure connection opening in the rotational direction of the first rotor.

According to subordinate claim 15, the end part is embodied as a bearing plate, in particular a B bearing plate. It is advantageous if it carries at least one bearing for bearing the rotor assembly. The end part is preferably removable.

A preferred embodiment of the invention will be described hereinafter by way of example, with reference to the accompanying drawings. The following are shown therein:

FIGS. 1 to 6 Cross-sections of a rotary piston engine according to the invention, which illustrate the sequential positions of the rotor assembly and their interaction with the intake connection, the pressure connection and the ventilation channel.

A rotary piston engine partially depicted in FIGS. 1 to 6 comprises a housing 1, which spatially limits a working chamber 2. An actuatable rotor assembly 3 is arranged in the working chamber 2. The rotary piston engine also has an intake connection 4, which opens out into the working chamber 2 via an intake connection opening 5. Furthermore, the rotary piston engine has a pressure connection 6 arranged at a distance from the intake connection 4, which pressure connection is in fluid communication with the working chamber 2 via a pressure connection opening 7. The rotary piston engine additionally has a ventilation channel 8, which opens out into the working chamber 2 via a ventilation channel opening 9.

The housing 1 is in multiple parts. It comprises a first bearing plate 10 and a housing base part 11 and also a second bearing plate (not depicted). The bearing plates 10 are arranged at opposite sides of the housing base part 11 in the assembled state of the housing 1.

The bearing plates 10 and the housing base part 11 together limit the working chamber 2. The bearing plates 10 spatially limit the working chamber 2 in the longitudinal direction or axially, while the housing base part 11 or its working-chamber wall spatially limits the working chamber 2 laterally outwards or radially outwards.

The working chamber 2 has a first working sub-chamber 12 and a second working sub-chamber 13, which are formed substantially identically. The working sub-chambers 12, 13 are arranged alongside one another and are in direct fluid communication with one another. They are open in relation to one another in a connection region.

A first rotor 14 of the rotor assembly 3 is arranged in the first working sub-chamber 12. The first rotor 14 is arranged non-rotatably on a first rotor shaft 15, which is mounted in the housing 1 in a manner in which it is rotatable or rotationally drivable about its first longitudinal centre axis 16.

The contour of the first rotor 14, depicted in FIG. 1, is point-symmetrical in relation to the first longitudinal centre axis 16. It has two first rotor blades 17 which are opposite one another, and which project from a first rotor base body. Each first rotor blade 17 has a first claw 18 and a first claw recess 19 limited by the first claw 18. The first claw recesses 19 are open radially outwards in relation to the first longitudinal centre axis 16. They are spatially limited by the first claws 18 counter to a first rotational direction 20 of the first rotor 14 and also partially radially outwards.

A second rotor 21 of the rotor assembly 3 is arranged in the second working sub-chamber 13. The second rotor 21 is arranged non-rotatably on a second rotor shaft 22, which is arranged in the housing 1 in a manner in which it is rotatable or rotationally drivable about its second longitudinal centre axis 23. The rotor shafts 15, 22 run parallel to one another.

The second rotor 21 is point-symmetrical in relation to the second longitudinal centre axis 23. It comprises two second rotor blades 24 which are opposite one another, and which project from a second rotor base body. Each second rotor blade 24 has a second claw 25 and a second claw recess 26 limited by the second claw 25. The second claw recesses 26 are open radially outwards in relation to the second longitudinal centre axis 23. They are spatially limited by the second claws 25 counter to a second rotational direction 27 of the second rotor 21 and also partially radially outwards.

The first rotor 14 and the first rotor shaft 15 are integrally connected to one another, for example. Alternatively, they are embodied separately. A similar situation applies to the second rotor 21 and the second rotor shaft 22.

Each rotor shaft 15, 22 is preferably mounted on both sides in the housing 1. The first rotor shaft 14 is preferably in drive communication with a drive. The rotor shafts 15, 22 are in drive communication with one another preferably via a synchronisation mechanism.

The first claws 18 are dimensioned or formed in such a way that they sweep closely along the housing base part 11 on the inside during rotation in the first rotational direction 20. The second claws 25 are dimensioned or formed in such a way that they sweep closely along the housing base part 11 on the inside during rotation in the second rotational direction 27.

The intake connection 4 is arranged in the first bearing plate 10. The intake connection 4 opens out eccentrically into the first working sub-chamber 12 and also into the second working sub-chamber 13 via the intake connection opening 5. The intake connection opening 5 is mainly located in the second working sub-chamber 13.

The pressure connection 6 is arranged in the first bearing plate 10. The pressure connection 6 opens out eccentrically into the first working sub-chamber 12 via the pressure connection opening 7.

The ventilation channel 8 is arranged in the first bearing plate 10. The ventilation channel 8 opens out eccentrically into the first working sub-chamber 12 via the ventilation channel opening 9. The ventilation channel opening 9 is arranged alongside the pressure connection opening 7. It is arranged between the intake connection opening 5 and the pressure connection opening 7 in the first rotational direction 20. With reference to the first rotational direction 20, the ventilation channel opening 9 is arranged upstream of the pressure connection opening 7 and downstream of the intake connection opening 5.

The ventilation channel opening 9 is substantially smaller than the pressure connection opening 7. It is substantially smaller than the intake connection opening 5, which is larger, in particular substantially larger, than the pressure connection opening 7. The surface area of the ventilation channel opening 9 is between 1% and 10%, more preferably between 2% and 5%, of the surface area of the intake connection opening 5. It is between 7% and 20%, more preferably between 10% and 16%, of the surface area of the pressure connection opening 7.

The operation of the rotary piston engine is described hereinafter. The first rotor shaft 15 is set in rotation about the first longitudinal centre axis 16 in the first rotational direction 20 by means of the drive. The second rotor shaft 22 is also set in rotation correspondingly via the synchronisation mechanism which is active between the first rotor shaft 15 and the second rotor shaft 22. The rotor shafts 15, 22 and thus also the rotors 14, 21 are driven in rotation in opposite directions. The rotors 14, 21 act together and are temporarily in meshing engagement with one another.

FIG. 1 illustrates a beginning of a suction cycle of the rotary piston engine. The intake connection opening 5 is only partially closed by the first rotor 14 and the second rotor 21. Conversely, it is partially open. Gas can therefore flow into the first working sub-chamber 12 and second working sub-chamber 13 via the intake connection 4.

The pressure connection opening 7 is completely closed by the first rotor 14.

The first rotor 14 and the second rotor 21 block fluid communication between the intake connection opening 5 and the ventilation channel opening 9. A first claw 18 of the first rotor 14 engages a second claw recess 26 of the second rotor 21.

The rotors 14, 21, together with the housing 1 in the working chamber 2, limit a suction or inlet space 32, which is connected to the intake connection opening 5 on both sides and extends into the first and second working sub-chambers 12 and 13. The suction or inlet space 32 becomes larger during the suction cycle by rotation of the rotors 14, 21. It is closed.

The ventilation channel opening 9 is completely open. It is uncovered. A working space 33, which is substantially spatially limited by the housing 1 and the second rotor 21 and is located in the second working sub-chamber 13, is about to undergo an isochoric transport according to FIG. 1.

Owing to the kinematics of the gas which are brought about by the rotation of the second rotor 21, a static negative pressure prevails in the working space 33 of the rotary piston engine in relation to atmospheric pressure.

In FIG. 1, an expansion/ventilation space 34 of the rotary piston engine extends in the first working sub-chamber 12 and the second working sub-chamber 13. It is spatially separate from the suction or inlet space 32 and the working space 33, The expansion/ventilation space 34 is spatially limited by the first rotor 14, the second rotor 21 and the housing 1.

In FIG. 1, the ventilation channel opening 9 is in fluid communication with the expansion/ventilation space 34. The expansion/ventilation space 34 is under positive pressure or negative pressure in relation to atmospheric pressure, depending on an operating point reached.

If positive pressure prevails in the expansion/ventilation space 34 in relation to atmospheric pressure, the expansion/ventilation space 34 or the gas enclosed there is expanded into the atmosphere via the ventilation channel opening 9 or the ventilation channel 8.

By contrast, if an operating point is reached at which an inner compression in the expansion/ventilation space 34 is insufficient in order to raise the static pressure to atmospheric pressure, negative pressure prevails in the expansion/ventilation space 34 also shortly prior to opening or reaching the pressure connection opening 7 in relation to atmospheric pressure. In this case, the expansion/ventilation space 34 is then ventilated atmospherically via the ventilation channel opening 9 or the ventilation channel 8. At this operating point, preferably less than 400 mbar(a) negative pressure prevails in the expansion/ventilation space 34 in relation to atmospheric pressure.

As FIG. 2 shows, an isochoric transport cycle. for the isochoric transporting of the sucked-in gas enclosed in the suction space 32, is connected to the suction cycle. The suction space 32 or the gas enclosed therein has been divided into/onto two separate, mutually separated transport spaces 28, 29 by rotation of the rotors 14, 21 in the respective rotational direction 20 or 27 by an angular range of 50° to 75°, which transport spaces face away from one another and are limited by the housing 1 and the respective rotor 14 and 21. Each first and second transport space 28 and 29 is arranged and closed off in the respective working sub-chamber 12, 13. The transport spaces 28, 29 and/or the gas enclosed therein are/is displaced isochorically. The rotors 14, 21 are disengaged. In particular, the claws 18 and 25 and the claw recesses 19, 26 of the rotors 14, 21 are disengaged. The second transport space 29 substantially corresponds to the working space 33.

The pressure connection opening 7 is for the most part open. The first rotor 14 opens the pressure connection opening 7. The expansion/ventilation space 34 has become smaller.

The intake connection opening 5 is still partially open. Gas can therefore enter into the working chamber 2 for a new cycle. The rotary piston engine with the rotors 14, 21 makes two intake and pressure cycles per rotor revolution possible.

The ventilation channel opening 9 is completely closed by the first rotor 14.

As FIG. 3 shows, a common working-space phase is connected to the isochoric transport cycle. The two transport spaces 28, 29 are combined to form a common working space 30 by rotation of the rotors 14, 21 in the respective rotational direction 20 or 27 by an angular range of 55° to 85°, which common working space is closed off. The common working space 30 is separated from the intake connection opening 5, which is partially open. via the rotors 14, 21. It is arranged at a distance from the intake connection opening 5. It extends via the first working sub-chamber 12 and the second working sub-chamber 13. A second claw 25 of the second rotor 21 engages a first claw recess 19 of the first rotor 14.

The pressure connection opening 7 is almost completely closed by the first rotor 14. The second rotor 21 blocks fluid communication between the pressure connection opening 7 and the common working space 30.

The ventilation channel opening 9 is completely closed by the first rotor 14.

By rotation of the rotors 14, 21 in the respective rotational direction 20 or 27 by an angular range of 5° to 35°, a dead-space-enclosure and dead-space-feedback phase, which is shown in FIG. 4, is connected to the common working-space phase. A dead space 31 is enclosed between the first rotor 14 and the second rotor 21 in a central region of the housing 1 in the working chamber 2 between the neighbouring claws 18 and 25, and, respectively, between the neighbouring claw recesses 19, 26. The dead space 31 is closed off. It is between the rotor shafts 15, 22. In the dead-space-enclosure and dead-space-feedback phase, the dead space 31 is enclosed and fed back to the intake region.

The ventilation channel opening 9 in this case is gradually released by the first rotor 14. The first rotor 14 opens the ventilation channel opening 9.

The pressure connection opening 7 is completely closed by the first rotor 14.

The intake connection opening 5 is still partially open.

By rotation of the rotors 14, 21 in the respective rotational direction 20 or 27 by an angular range of 45° to 75°, a ventilation-channel opening phase, shown in FIG. 5, is connected to the dead-space-enclosure and dead-space-feedback phase, in which ventilation-channel opening phase the ventilation channel opening 9 is completely open and the working space 30 is filled with ambient air and charged to ambient pressure. The working space 30 becomes smaller in its volume. Pressurised air or vacuum can therefore be produced conveniently. The first rotor 14 is twisted in comparison with the ventilation channel opening 9.

The first rotor 14 also gradually releases the pressure connection opening 7. It opens it. Gas can therefore leave the working chamber 2 via the pressure channel 6.

The intake connection opening 5 is still partially open.

The rotors 14, 21 are disengaged.

By rotation of the rotors 14, 21 in the respective rotational direction 20 or 27 by an angular range of 5° to 30°, a further phase, shown in FIG. 6, is connected to the ventilation-channel opening phase, in which further phase the ventilation channel opening 9 is completely closed by the first rotor 14. The rotors 14, 21 are disengaged.

The pressure connection opening 7 is at least partially open.

The intake connection opening 5 is still partially open.

There then follows again the suction phase shown in FIG. 1. In the case of a rotary piston engine embodied with double rotor claws, two intake and pressure cycles are performed per rotor revolution.

The first rotor 14 forms a control rotor in relation to the ventilation channel opening 9. 

1. A rotary piston engine, comprising a) a housing (1) spatially limiting a working chamber (2), b) an intake connection (4) for guiding gas into the working chamber (2), c) a pressure connection (6), connected to the working chamber (2), for guiding the gas out of the working chamber (2), d) a rotor assembly (4) having i) a first rotor (14) rotatably arranged in a first working sub-chamber (12) of the working chamber (2), and ii) a second rotor (21) rotatably arranged in a second working sub-chamber (13) of the working chamber (2) and cooperating with the first rotor (14), and e) a ventilation channel (8), formed in the housing (1) and connected to the working chamber (2) via a ventilation channel opening (9), for the temporally limited introduction of air, in particular ambient air, into the working chamber (2), wherein the ventilation channel opening (9) i) is open, in particular completely open, at least in sections in a compression phase.
 2. The rotary piston engine according to claim 1, characterised in that it is one-stage.
 3. The rotary piston engine according to claim 1 or 2, characterised in that the ventilation channel opening (9) is controllable, in particular releasable and/or closable, via the first rotor (14).
 4. The rotary piston engine according to any one of the preceding claims, characterised in that the first rotor (14) and the second rotor (21), prior to the compression phase, limit a common working space (30) in the working chamber (2) in a common working-space phase, wherein the ventilation channel opening (9) is completely closed, in particular by the first rotor (14), in the common working-space phase.
 5. The rotary piston engine according to claim 4, characterised in that, in the common working-space phase, the pressure connection (6) is separated completely from the common working space (30), in particular by the first and/or second rotor (14, 21).
 6. The rotary piston engine according to claim 4 or 5, characterised in that, in the common working-space phase, dead space (31) between the first rotor (14) and the second rotor (21) is completely spatially separate in relation to the common working space (30).
 7. The rotary piston engine according to any one of the preceding claims, characterised in that the pressure connection (6) is completely closed in the compression phase.
 8. The rotary piston engine according to any one of the preceding claims, characterised in that the ventilation channel opening (9) is completely closed, in particular by the first rotor (14), in a pushing-out phase.
 9. The rotary piston engine according to claim 8, characterised in that the pressure connection (6) is at least partially open in the pushing-out phase.
 10. The rotary piston engine according to any one of the preceding claims, characterised in that the ventilation channel opening (9) is completely open prior to opening of the pressure connection (6).
 11. The rotary piston engine according to any one of the preceding claims, characterised in that the ventilation channel opening (9) is arranged in a pressure region of the rotary piston engine.
 12. The rotary piston engine according to any one of the preceding claims, characterised in that the ventilation channel opening (9) is arranged alongside a pressure connection opening (7), arranged in the working chamber (2), of the pressure connection (6).
 13. The rotary piston engine according to any one of the preceding claims, characterised in that the ventilation channel opening (9) opens out into the working chamber (2) at a distance from the dead space (31) between the first rotor (14) and the second rotor (21).
 14. The rotary piston engine according to any one of the preceding claims, characterised in that the ventilation channel opening (9) is completely closed, in particular by the first rotor (14), during closure of the dead space (31) between the first rotor (14) and the second rotor (21).
 15. The rotary piston engine according to any one of the preceding claims, characterised in that the ventilation channel (8) is arranged in a first end part (10) of the housing (1), which is embodied as a bearing plate, in particular a B bearing plate.
 16. A method for operating a rotary piston engine according to any one of the preceding claims, comprising temporally limited introducing of air, in particular ambient air, into the working chamber (2) via the ventilation channel (8) during the compression phase. 